Yes, while you might scoff and say, “But I’ve sat on the sea bottom myself and all I got was a dodgy encounter with some crabs,” we’d hasten to make the point that the director of Avatar headed for the deepest point in the ocean, the Mariana Trench, which is nearly seven miles deep. Need some facts to exploderise your brain shell? The trench is 120 times larger than the Grand Canyon and more than a mile deeper than Mount Everest is tall.

Only two men have been to that depth before – and that was together, in 1960. Cameron has been preparing for seven years and had to wait out days of bad weather before he could take his solo sub, the Deepsea Challenger (which he helped to design and develop, of course) down. He landed at 2:52pm PST and tweeted, "Just arrived at the ocean's deepest pt. Hitting bottom never felt so good. Can't wait to share what I'm seeing w/ you.” Even at the deepest point in the ocean, James Cameron gets better Internet service than most of us. Life? Just not fair.

He’s since tweeted that he made it back safely after shooting 3D footage and still pictures of the area and any life. He’s also taken samples of sediment and small sea creatures. Given how much he’s talked about exploring Pandora’s oceans in the planned Avatar sequels, we bet he took copious notes, too.

Of course, this isn’t Cameron’s first trip underwater by a long shot; he was previously known as one of the few people in the world who have explored the wreck of the Titanic. Wait a minute... The film about that ship arrives back in cinemas next month! The cheeky blighter's gone and done this as a way of building awareness!